Trust me mate, it doesn't matter how many years you've been growing... you are always going to get new challenges and obstacles, or the same issues rearing their ugly head... and unforeseen problems. It's just part of outdoor growing.
If it's not deer eating your plants, it's rabbits. Or rats! Or a kangaroo! If it's not mammals, it's slugs and snails. If it's neither of them, it's caterpillars. Or other bugs. Or a strong gust of wind snaps your plant in half. Or it's massive flooding, or a heatwave. Or hail stones. Or the plant just gets affected by a deficiency, or illness, and withers away and dies. Or mould ravages your buds. And if it's none of that... it's thieves stealing your plants. Or someone discovering your crop and tipping off the police. Or construction workers clearing the land. Simply put... I have never had a season, free of major issues and plant losses. You're always going to encounter something, so don't get dejected when you do experience losses. Growing on your own property minimises those risks enormously, providing it is legal where you are. Unfortunately that is not the case in the UK & Oz.
The bottom line is to always expect some losses, which is why it is never a good idea to just put 1 or 2 plants outdoors. You will encounter certain problems in your first and second years, and learn to refine your technique to help prevent those issues, only for different problems to appear the following year. And so on. Then you get all these different issues under wraps, and think you're bulletproof and fully prepared for the season ahead, only to get caught out by the same problems again. Or another new problem rears it's head. In my case, it was the caterpillars this year.
My first year growing, I started out with 15 plants and only got 3 to harvest with 80% losses. This year my losses are at around 20% due to slugs/snails munching 2 seedlings and the caterpillars devastating one of my autos. Also, I know a big time grower on a different forum that has been growing outdoors for 10 years+, and he has just lost 50% of his plants this past week. So always expect the unexpected and account for losses. Sounds like you're planning for that though by putting out decent numbers. If I was you, I would also be caging my plants with wire mesh. Otherwise next year you might find out why so many of us outdoor growers have to put wire mesh around our plants...
All the best [emoji106]